1. Field of the Invention
The invention relates to a ski with a special profile, more particularly intended for the practice of alpine skiing, comprising a central region called a "central zone", on which the bindings for the skier are positioned, and two end regions, one called the tip and the other called the heel.
2. Discussion of the Related Art
Traditionally, most skis currently available are symmetrical with respect to their longitudinal mid-plane, so that the right ski is entirely interchangeable with the left ski. In fact, it has generally been considered hitherto that this lack of differentiation of one ski with respect to the other was of no consequence or of very little consequence as regards actual skiing.
Now, the advantage of having asymmetric skis, namely a right ski and a left ski, has been realized, in particular as regards the level of efficiency of setting the edges and thereby the response of these skis.
It has already been known for a long time that this edge setting is particularly efficient at the inner edge of each ski. It is therefore important to have available a ski through which the action of the skier is amplified on the inner side, this amplification being obtainable, for example, by increasing the density of the ski at this location, or its thickness, in order to increase the efficiency of the pressures applied by the skier.
In parallel, it is undoubtedly important to be able to optimize the action of the inner edge of the ski more particularly at the central zone, and it is also expedient to be able to "cut" into the snow at the outer ends of the ski, that is to say close to the tip and the heel, in view of the fact that, during turning, the ends of the ski side-slip and that, in particular, this side-slipping also occurs with a slight pivotal movement with respect to the central zone, so that the said ends are in a relative rotational movement with respect to the said central zone and must therefore be able to move almost freely whatever the condition of the snow, whence this requirement of giving them this ability to penetrate, which is obtained only with thin ends, more particularly at the front and rear contact lines respectively.
Now, these various requirements have never been combined simultaneously within one and the same ski, in view of the apparently conflicting results which they seem to generate. In addition, other constraints, such as the flat positioning of the bindings, the height of the foot of the skier on the ski and the weight of the skier, have prevented the development of its shape.
In order to give the ski some degree of rigidity in simple bending, that is to say perpendicularly to the plane defined by the surface of the sole, they have been fitted with a longitudinal rib, which is strictly linear, positioned along the mid-line of the ski. This rib is continuous (see U.S. Pat. No. 2,158,325) or discontinuous (FR-A-2,523,460), which, in view of its position, gives the ski thus produced no asymmetry.
Asymmetric skis have also been proposed in document DE-A-1,939,540, in which the top located on the inner side of each of the skis of one and the same pair is parallel to the surface of the running sole, while the outer side, except optionally at the central zone, is inclined. Although admittedly it is thereby possible to obtain the effect of cutting into the snow at the outer edge, this type of ski nevertheless does not improve the efficiency of setting the inner edge.